MDS PREP
Filament in X-ray tube is heated by
1) Step-up high voltage transformer
2) Auto transformer
3) Step-down low voltage transformer
4) Ammeter
Radiology
Answer: 3
In an X-ray tube, the filament (cathode) is heated to produce electrons through a process called thermionic emission. This heating is accomplished by a step-down low voltage transformer, which reduces the high voltage from the power supply to a lower voltage suitable for heating the filament. The step-down transformer ensures that the filament receives the correct amount of current to achieve the necessary temperature for electron production.
Zygoma fractures can be best viewed by
1. Occipitomental view
2. Lateral oblique
3. Towne"s view
4. True lateral
Radiology
Answer: 1
Zygoma fractures can be best viewed by occipitomental view.
Inventor of orthopantomographic machine is
1. Hounsfield
2. Roentgen
3. Kell
4. Namata
Radiology
Answer: 4
The inventor of the orthopantomographic machine is Namata.
Minimal dentinal destruction to get evident on the radiograph
1) 30 microns
2) 40 microns
3) 200 microns
4) 300 microns
Radiology
Answer: 2
Radiographic detection of carious lesions or dentinal destruction typically requires a certain threshold of loss of tooth structure. Studies have shown that a loss of approximately 40 microns of dentin is necessary for a radiograph to show evidence of carious lesions.
Interproximal caries is best detected by
1. Bitewing radiography
2. Periapical
3. Occlusal
4. None of the above
Interproximal caries is best detected by bitewing radiography.
In bone scintigraphy all is guessed except
1. Avascular necrosis
2. Fractures
3. Osteomyelitis
4. None
Radiology
Answer: 4
In bone scintigraphy, all is guessed except none.
Lateral cephalogram is used for all of the following except
1. To assess where excessive growth is occuring
2. To compare the growth patterns with previous radiograph
3. To assess level of posterior alveolar bone
4. To assess soft tissue profile
Radiology
Answer: 3
A lateral cephalogram is used to assess the level of posterior alveolar bone.
Salt-paper appearance is seen in intraoral periapical radiograph of
1) Thalassaemia
2) Sjogren"s syndrome
3) Periodontal abscess
4) Osteoporosis
Radiology
Answer: 1
The "salt-paper" appearance in intraoral periapical radiographs is often associated with thalassemia due to changes in the bone structure.
In thalassaemia, particularly in the case of thalassaemia major, there can be
changes in the bone structure due to marrow hyperplasia and compensatory
changes. This can lead to a "salt-and-pepper" or "salt-paper" appearance on
radiographs, which is characterized by a mottled pattern of radiolucency and
radiopacity in the bones, including the jaw.
Osteoporosis can lead to generalized bone loss and may show decreased bone
density on radiographs
A periodontal abscess typically presents as a localized radiolucency around
the root of a tooth on radiographs
Sjogren's syndrome primarily affects the salivary and lacrimal glands,
leading to dry mouth and dry eyes